The present invention relates to a novel xanthine derivative having a diuretic action, a renal-protecting action and a vasodilative action.
Heretofore, theophylline, i.e., 1,3-dimethylxanthine has been known as a diuretic, a vasodilator, etc. [The Merck Index, 10th edition, 9114 (1983)].
Theophylline analogues represented by the following general formula (I) wherein both R.sup.4 and R.sup.5 are alkyl have a diuretic action, as disclosed in East German Patent No. 31,772 [Chem. Abst., 63, 18120d (1965)] (CA-724,173A); J. Am. Chem. Soc., 75, 114 (1953) and J. Med. Chem., 14, 1202 (1971), and also have a bronchodilative action, as disclosed in Japanese Published Unexamined Patent Application Nos. 166191/81 (U.S. Pat. No. 4,546,182), 163381/82 (GB-2091249A) and 41478/88 (EP-256692A). Furthermore xanthine derivatives having an anti-inflammatory action and other activities are disclosed in Japanese Published Unexamined Patent Application No. 66583/80 (U.S. Pat. No. 4,299,832); Japanese National Publication of translated version No. 500666/86 (U.S. Pat. No. 4,558,051); U.S. Pat. Nos. 3,624,215 and 3,624,216.